Enhancing ResourceBundleMessageSource to Support Multiple Message Files in Micronaut

[rsalbergaria]

We are currently in the process of migrating our Java workloads from Spring to Micronaut. During this transition, some of our teams that previously used Spring have raised concerns regarding the behavior of the ResourceBundleMessageSource in Micronaut, specifically in how it handles resource message files.

In our Spring setup, we have a common practice of utilizing message files from both a shared library and individual microservices. This allows us to aggregate messages from both sources, effectively treating the resource bundle reading as a list. However, we've noticed that in Micronaut, ResourceBundleMessageSource seems to be limited to loading only one bundle by its name, which poses a challenge to our current approach.

Given this context, we are interested in exploring the possibility of enhancing the ResourceBundleMessageSource in Micronaut to support the aggregation of messages from multiple files, similar to our existing setup in Spring. This feature would greatly facilitate our migration efforts and ensure consistency in how we manage our internationalization resources across our services.